Tuyere



July 20, 1965 R. E. ZIMMERMANN 3,

TUYERE Filed Nov. 5, 1962 2 Sheets-Sheet l FEED B/N INVENTOR.

E0852 T E. Z/MMEEMANN BY 4 TTOENE Y July 20, 1965 R. E. ZIMMERMANN 3,195,874

TUYERE Filed Nov. 5, 1962 2 Sheets-Sneet 2 INVENTOR. IF 5 ROBERT E. Z/MMEEMANN ,w 1% Away,

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A T TOENE Y United States Patent 3,195,874 TUYERE Robert E. Zimmermann, Genoa, Italy, assignor to Keppers Company, Inc., a corporation of Delaware Filed Nov. 5, 1962, Ser. No. 235,204 1 Claim. (Cl. 266-411) This invention relates to an improved apparatus for the injection of solid particulate material into a metallurgical furnace such as a blast furnace, and more particularly to an improved tuyere for the injection of coal particles into a blast furnace. Various forms of tuyeres have been designed to allow such injection of particulate material into a metallurgical furnace. Two systems have been proposed heretofore for injecting solid materials, particularly solid fuel, into a blast furnace. One system has used lances to convey the solid materials through the blowpipe into the bore of the tuyere. The other system has involved a passage within the body of the tuyere for the injected. material.

The lance has the disadvantage of being limited as to the temperature which it can withstand unless it is cooled in some manner, and also, the lance partially obstructs the bore of the tuyere. This obstruction impedes both the air flow and the view of combustion at the nose of the tuyere through the peepsight. If the lance is liquid cooled, it necessarily becomes appreciably larger in diameter thereby increasing the obstruction. When the lance is air cooled as a consequence of using air as the carrier for the injected solid, an excess of the cooling air is needed. This excess of air is undesirably inefiicient. When cool air is used as the solid conveying medium, cooling of the lance is normally no problem if there is sufficient air fiow with the injected material. However, when using high rates of solids injection, with high hot blast heat requirements, it is desirable to reduce the volume of the injection air to the minimum volume needed to convey the solid so that the temperature at the tuyere Zone is maintained as high as possible. In this manner, the injected material and the sensible heat of the hot air blast becomes most effective. With such high rates of solid injection and hot blast heat requirements however, it is entirely possible that the injection air will be insufficient to cool the lance thereby causing deterioration of the lance itself and in addition, there will be a partial thermal decomposition of the injected material.

A tuyere, in which a passage for the injected material is provided within the body of the tuyere itself, provides a water-cooled duct for the injected solid and its convey ing air until contact is actually made with the hot blast air. Temperature does not, therefore, pose any problem for either the injection duct material, or the injected particles. Such tuyeres have heretofore had the disadvantage of being more or less a permanent part of the blast furnace, requiring a shutdown of operations to change from one tuyere to another. This is necessary 'if the cooling Water jacket breaks thus causing the coolinjected solids are obtained. By the'use of this novel ,tuyere, the life of the tuyere is not shortened despite the injection of abrasive material. Tuyeres normally have a useful life of six months and upward in their single function to introduce heated air into the interior of the blast furnace. For the tuyere to be adapted to perfrom the dual role of both injecting solids and hot blast air it is essential that the provisions for solids injection do not shorten the $385,874 Patented July 20, 1965 useful life of the tuyere for its primary function of introducing heated air. Tuyeres are normally made of high purity copper (99.7 percent or more) so that the heat conductivity is as good as can be obtained, but this purity does not give the material any great resistance to abrasion. In the case of fluid injection, such as air, abrasion is not a significant problem and the tuyere can be small in diameter with high pressures used to give the required load per hour. With solids injection, the diameter of the injection duct could definitely limit the rate of injection because solids can not be compressed and the problem of abrasion becomes a significant one.

Because of the physical dimensions of the conventional tuyere, it is undesirable to obstruct the flow of cooling water circulating in the body by any thick-walled copper secondary injection duct running through the water chamber. However, the wall of this injection duct can not be thin copper because of the abrasion wear which would be caused by the injected solids. Accordingly, the injection duct passing through the body of the tuyere must be made of some material with abrasion resistant characteristics or must be so constructed that an abrasion resisting surface can be inserted where the flow of solids would cause wear.

The improved tuyere of this invention comprises a tuyere body having a wall, a cooling jacket therearound, and an injection duct for the solid particulate material extending through said cooling jacket. The tuyere wall has a hallow protrusion thereon adjacent the discharge end of the injection duct whereby the injected particulate material will pass into an air stream flowing from the inlet end to the outlet end of said tuyere body. In one embodiment a target may be placed adjacent to the outlet end of the injection duct to deflect the particles into the air stream and in another embodiment the protrusion extends to the outlet end of the tuyere body. The injection duct may or may not be lined with an abrasion resistant lining, such as a heat resistant ceramic material or other abrasion resistant material. The injection duct is threaded and therefore may be readily unscrewed and replaced when necessary.

The following decription of the invention is described with reference to the accompanying drawings in which- FIGURE 1 is a schematic elevational flow diagram of a typical injection system.

FIGURE 2 is a cross-sectional view of the improved tuyere of the invention.

FIGURE 3 is a transverse cross-sectional view of a portion of the tuyere of the invention taken on lines 33 of FlGURE 2.

FIGURE 4 is a pictorial view of the abrasion resistant target of the invention.

FIGURE 5 is a cross-sectional view of an alternate embodiment of the tuyere of the invention, and

FIGURE 6 is a transverse cross-sectional vieW taken along lines 6-6 of FIGURE 5.

Referring to the FIGURE 1 of the drawings showing a plant for the injection of coal into a blast furnace; coal arriving at the plant from the mine or from storage is dumped into a hopper it) from which it is carried by belt 12 to an impact crusher 14. The crushed coal is transferred by bucket elevator 16 from the crusher to a vibrating screen 18 of predetermined size. The oversize particles which are retained on the screen return to the hopper l0. Undersize particles which pass through the screen are fed through chute 20 to belt 22 which transports the material to a reversible shuttle conveyor 24 comprised of two conveyors 26, 23 which deposit the repared coal evenly in rectangular feed bin 30.

Underneath the bin 31) are a plurality of hopper devices 32 each delivering particles to a coal feeder 34. The bin 3%) is mounted on load cells (not shown) so that the Arr weight of coal particles in the bin coalbulk'density due and coal pulverization.

Compressed air is supplied to variations in moisture content to all the coal feeders 34,

by supply means 35 through a common header 36 from which parallel branch lines 38 flow to the individual units,

The coal-air mixture leaving each coal feeder flows through a transfer line 40,:which may be several hundred feet long depending on the particular plant layout, to the splitters diagramatically shown at 42 located near the bustle pipe-43. After'the; splitters, the, branch lines 44 lead to alternate tuyeres 45 of a blast furnace 46.

The foregoing system is described in greater detail in.

a copending application by Elwood V, Schulte and Elliott .Preston assigned to the assignee of the present invention.

can-be determined periodically to obtain acheck on the feed rate. This. aids in making minor adjustments in coal feeder speed which would be necessary because of gradual changes in a, a 4' i I fixedly attached thereto, thethreaded plug being adapted "to be fitted into a tapped hole in'the rearwall 166 of the coolant chamber 152. In this manner the injection duct 1562 may be readily, removed and replaced'by merely unscrewing the threaded plug 164 fromthe tapped hole in the rear wall 166'while simultaneously unscrewing the threaded end of said injection duct 162 from the tapped hole in outer wall 160 of protrusion 154. The injection duct 162 is provided with an abrasion resistant lining 168. The lining 168 may be composed,- for example, of a heat resistant ceramic or equivalent material'.1 The outer end of the'heat resistant lining 16 8 is flared as shown at170- The injection duct;1 62 is removably attached to feed line 44 by means of coupling 172 threaded thereto;

The hereinabove described embodiments are modificationsiof a conventional tuyere which modifications allow a for the handling of abrasive materials to be injected into In accordance with this invention, a novel tuyere: is l provided which has the dual function of injectinghot blast air into the furnace and simultaneously injecting solid particulate material into the furnace. 1 i a The improved tuyere (FIG. 2) will be seen to cornprise a tuyere wall 48 comprising a right frustoconical section, and alcooling jacket 50 substantially completely enclosing said tuyere wall 48 with a coolant chamber 52. A hollow protrusion 54 is formed in the tuyerewall 48 Which'hollow protrusion has side Walls 56 which slope outwardly as they approach the tuyere Wall 48. The protrusion 54 also has an inner wall 58 and an outer wall 60. .A tapped hole is provided in said outer wall 600i the furnace, The improved tuyere can be readily cast in thefoundry and completed in a machine shop. The modifications comprise altering the tuyere to permit a straight injection tube of hard stainless steel or similar material Y to be inserted into the tuyere body to act as an injection said protrusion 54 forthe insertion therein of the threaded j end of an injection duct 62. The injection ducti62 "is also provided with a threaded plug 64 fixedly attached thereto, said threaded plug being adapted to be fitted into a tapped hole in the rear wall 66 of said coolant duct. In FIGURE 2 the injection'duct'is arranged. to have the injected'solids be deflecte'dcinto the tuyere bore by a target ot'abrasionresistant material. In the embodimerit shown in FIGURE 5 theinjection duct has a thinner wall with a ceramic tube liner. 'This type of lined duct could also be used, if desired, in theembodiment shown in FIGURE 2. The .use of. the embodiment shown in FIG- URE 5 permits the injected solid particulate material to contact the hot blast air. in the' tuyere bore at a notch in theperiphery of the nose; A downwardly sloping bore is shown 'for' the tuyere similar to the conventional Weir tuyere, because this feature makes more certain the water I coolingof the tuyere around the notch.

chamber 52. Inthis manner the injection duct 62 may be readily removed and replaced by merely unscrewing.

the threaded plug 64 from the tapped hole in rear wall 66 while simultaneously unscrewing the threadedend of said injection duct 62 from the tapped hole in outer Wall of said protrusion-54. An abrasion resistant target In the embodiments shown water cooling has not been v impaired since the thin wallsof the inserted injection duct should provide for ample cooling circulation. A curved duct'has been avoided since it would be difficult to insert and align a curved duct, and a curved duct would 68 is provided adjacent inner wall 58 of protrusion-54.

The angle of the inner wall 58 and the abrasion resistant target 68 can be varied'to deflect the injected solidsinto the tuyere atany particular predetermined angle. ZAbrasion resistant target is in the shape of the surface of a semi-hemisphere so as toccompletely cover'any portion of the tuyere body that may be subjected to the abrasion of the injected particulate material While simultaneously deflecting the particles in a predetermined direction.

Abrasion resistant target 68 may be composed for -example of a material such as tungsten carbide. In this mannenjthe soft copper of cwhich'the tuyere body and cooling jacket is composed will not be deleteriously affected by the injection of 'solidparticulate material.

FIGURES 5 and 6 show an alternate embodiment'of the tuyere of the invention which embodiment has the additional advantages of eliminating the necessity for the abrasion resistant target, and providing. for better ing of the tuyere and injection duct. j

In the embodiment of FIGURES 5 and 6 there is shown a tuyere which will be seen to comprise a tuyere wall 148 in the shape of a generalfrustoconical section and coola cooling jacket 150 completely enclosing'the tuyere wall 148 with a coolant chamber 152. A hollow protrusion 154 is formed in the tuyere wall 148 which protrusion has side walls 156 which slope outwardly as theyapproach the tuyer wall 148. The protrusion 154 is provided with an outer wall 160 whereby the coolant chamber is completely sealed. A tapped hole is provided in ,wall 160 of said protrusion'154 for the insertion therein of the threaded end of an injection duct "162. The injec- .,tion duct162 is also provided witha threaded plug 164 Iclairn:

inherently 'bersubjected to more adbrasive wear than a straight tube. Once thetube and plug assembly has been fastened togethen it could be changed as a unit since the plug and the threaded end. of the tube would both havethe same number of threads per inch.

A tuyere for use in "injecting hotblast air and solid particulateinaterial into a blast furnace comprising:

(a) a first conduit having an axis of flow;

'(b) an outer'wall surrounding said first conduit in spaced'apart relation thereto; 7

(c) end walls connecting .said first conduit and said outer wall and: forming an annular cooling space iaroundsaid firstconduit; i Y

7 I (d) a hollow protrusion on said first conduit disposed (g) means to flow: a stream of air and solid particulate matter in said second conduit 7 (h) a target disposedwithin saidhollow protrusion and obliquely positioned to said axis of flow whereby the 7 .solidparticulatematter flowing from said second conduit into 'said hollow protrusion strikes said obliquely positioned target and is deflected thereby into said flow of blast" air, said target being semihemispherical in shape, and said second conduit and said semi-hen1ispherical target being capable of resisting abrasion by said particulate matter.

References Cited by the Examiner UNITED STATES PATENTS 966,704 8/10 Pickles 266-41 1,873,996 9/32 Cunningham 26641 2,023,025 12/35 McKee 26641 6 FOREIGN PATENTS 114,667 10/29 Austria. 679,755 8/ 39 Germany.

5 WHITMORE A. WILTZ, Primary Examiner.

JAMES H. TAYMAN, 111., MORRIS WOLK,

Examiners. 

